SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8344e4a5724d4241dcf3a4046161494ece29a2573b003521602398551850c180' 
  AND token = '8v9e3EN6V6koSuOpzjpFHhAKGgvb6Kyuyvz0tqDDTwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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