SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e961e5eeb67c90eae89c410f4522141323f562ca7ea6c4959ddbf4704273068' 
  AND token = 'LlKN20mECoPJSj+QeG09c+6lmoYs4nA97jlUEHPVPG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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