SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79bc04878072c526ef10e3bc0e35c05b03894eebb7fe3e689cad56b6cbef700c' 
  AND token = 'LF/WlssL/TX+1GcSUQiynM9ec8hShL/XypaBXWiyrd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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