SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f0681b8beec83804fe427cad5f052c63772b22ae2bb1ad5d13953550a078e2b' 
  AND token = '1DqUboWk8i4Y4imPV3cXZD27J1lcGKOAUIbTr9B+JFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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