SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5d6b10ab37f6681a9a46a081713c645700422c3c85f7a2b16fc38a525149011' 
  AND token = 'jXuJuPzJIPUGVwYf2zCeJ+A7RHE6JmTmc7SB57PwbH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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