SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '578073fb685994d3294c00990c4d4c3d0b3848f370b9fd469155bc3f1c7eb69a' 
  AND token = 'wOTpr9pDsA+M4Y9YUOChXfg2F0EYrvOG/+Qo11Qbaxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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