SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecd44f10c0f523bb012bc73a70dbeec325ea0fc72d5ad94e4cd3d4bf631a77ca' 
  AND token = 'c16+5ttMgXR1Gbs2kTJgPhVj1ObK4WEYZYdWm6pmtvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}