SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acb9313ca94f0b8164436fbc1bcbcd00aff023fb47e1d9a6c386b5da6ce2d1b1' 
  AND token = 'r1RVDawCxlpVPbQhzB3U4NWAzs1qPmtGAZ4BHo+xN7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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