SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e0e27b1f3cdb5543a5acfce91f735b05f2a4deede882c2c7e82437db5ff9383' 
  AND token = 'veXTyYsT95rBzpkh3t7Vfq+ABCJDwEV7m1hhBqcOsNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}