SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c99a6cbb3bd759db7fabf33f128d01cc9e7caae5ac69153b7b73a36b44d83491' 
  AND token = 'DqV3cXyB8sg77s/48jf5uCi7+mgfcLoeQGuQNmVCboo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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