SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2bcdb719a7fda3bf5074596a7906b6a3814b1800d0a12a7a2054c173b66f45a' 
  AND token = '8vhxZDxRwQGroEzPyNfMC3dIOxO7o+AdM5aViRfIKew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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