SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff9195a11c2c17d6db5a32fd2cc0fe2917bde648a422bd11b451bf3b42893efc' 
  AND token = 'qUmD86LU3zCbdZSwzxcj9GKYfMATVUm/Qt2MDzpvSEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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