SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f3bcdccea928ba18a60cec9f551160848eceafbd775a53167c5c0e26bad57c3' 
  AND token = 'BAdyayFOc8+8y/fDcSgBXRMwoRDGPyKU+mqMnhPSKMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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