SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2509b68f5e175f78c389dfa3dbafda377ed380adfd6a030cf039b0d5765374c4' 
  AND token = 'ufpmUGMQ83WIcbae8FBjeuMdAu73U+U+69LKMnqP1Fc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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