SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75e7e50d2a17c5275e9f2078b87997759765a478ec77820002db737656061567' 
  AND token = 'fRi1oPaFhouXvmtTZgRQGuguFDY/dQuaFQLQK4acmhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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