SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66f3e3fcd5b080371cec169bacd8a6277c051a50f8f6d03ef1558d1d5e012724' 
  AND token = '0gPVwhrNdmqlEoKYGstlFMhxaEXqM8EjJm7EKqSfB+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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