SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a942d4085ff24c28653d162cb00ee9fd0e713bb386f96f2bfd3435948f090f8' 
  AND token = 'tIj37yko0k/D0yVCxjvf0PAFFfP4TKAlsFxDNgMlD4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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