SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce876aa41c4968829deaf662372a58570b9163163c1345086b4a820728ca410e' 
  AND token = 'hGYsbKwNZyAz+gpjuzoF1NgD29Ba5YQ3moJ9nMjkpM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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