SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27920879f07f5fd202dbb481506fda32309b4a1c04e3ae03e80fd384bf3874f3' 
  AND token = 'MoFyI7xUn71IPcRh1qhWwR1ty3Mrd7MxJfCcMxCfusQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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