SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2857c0263e517eb1790abf8f4e98d59b31c3ad26d8ccd4ea7f98e6d9cb35013c' 
  AND token = 'ZbHMlJrejMpMBnC2uL+YV5qp6V2QicdCQhYk3FbX+Dc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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