SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca165548a9eba361ef2943103726e7175664578fbcf5162b66114d4185c7c2e6' 
  AND token = 'NyvWIiIZUyywSwQk8aNw2gNpdArj3+/Dgh4gfHENp14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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