SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fa0e7e801252fd6b1988880f79f8db83c836df04a2c822b0cdb56805d147853' 
  AND token = 'V4Nhzl+JH4eNuM0BvRG1/oNLLpbZI3Y+Ll99cVU/owg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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