SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c4fd3b958ea851baf10c99054b2f435c9c349752975a1011f29a62229e31dd4' 
  AND token = '5wxvOzfmCxpt2wisUstFrDvzm6tTRDW04i+5SbZwZ24=' 
  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"
    }
  }
}