SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5faaf4eb40be48f407f50c38726c6a2139529c41461fdc8bc9b062d864bb4526' 
  AND token = 'B5tkI3fgvfAQT1fTmen2MlhwAbecFTAecrFKQo3jRlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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