SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd15fe6f7c3d313243bce7396afe9ae5c8acb5763816ac95aafa6ed3a47431fe' 
  AND token = 'zxvLT3ryn6/DC+A345jU4QW7waHejaZwu2dFDaz/cLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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