SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbb3fa2c16b244de27fbfab0b09776d864fd3587a357c468ecc0a41c75d88e13' 
  AND token = 'bHxHCzWFzlme7lJRyHkeeUMcTnAPReVhTRyvvKhXWuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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