SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a1659f3628e7b8863b144f9a2e3b26c35d9d07fd5577b08df5a5b39dc9dd76c' 
  AND token = 'oUgj8tlKKjX4/Atb/jPWz41XMLWfhUKU2+CBWAmS/O4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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