SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a0d23b0a87fb1fb9c5e02f66b5725d95fd354520e3731bae3c5af47a01ee146' 
  AND token = 'RRwytrnivOQEPt3XSd17BbJFWpAIU69FY7c5L+HZ2yw=' 
  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"
    }
  }
}