SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '798565c77d69b4300cae54afde3d234f9fcf925b59381bbb42878fcfd2163d2d' 
  AND token = 'zcOrSwEpmNj6WacBQnbDJ56njFyRtSOKx/P0CU0b2R4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}