SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c7f9cd434200e1c75a180b57d213e9c9de43917be1a57eb2a755ce4bbf8b95c' 
  AND token = 'yM2I1cKjuCtg1s1/HFRGOjlVRtYKuHN6PTjWaLlUOUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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