SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e56c8bd4b40cbd9dfa7be133d724cc75dd0fbbbdae970d7c4b2010de8b41215' 
  AND token = 'xtUd/T1wsR1tHbYQiYCimqYVXEfaxkVVNXYu2mfma5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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