SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf633b755a00cad1e7c1edb79480eefbc9b6d5b63023071073bb020794375cd9' 
  AND token = 'oub0ddcQSjxxh/8Zp/czKvSyUQbtOPBnB6gGvaQ/lxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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