SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59d4586a6126f445352cd3a66051513a24ad009fbe85c78032b4dc3185f78866' 
  AND token = '8dgzRtCA65GZrSM7R0XhlEVfiI6tJmzcTL382hlYjXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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