SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9f39d89967de920ef7d26ea7b2c90fcc1f83a86724cac1faf810c7c22301b8' 
  AND token = 'sArnO/xL0IRAImaArPMtEf8gJECGssuIN9zCoFwqRQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}