SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2dcf987d0092cc4a697ade957b56b8638e319649edd02fee83397b1b647b0bb' 
  AND token = 'QY6U/91MsHbfUu7otqwwk3y3LgD76nyCoZF5RVlgthQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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