SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b463f4cbdce7786245d704f008e7644eae34061623e26fd35663b24e019a56cf' 
  AND token = 'WCwkBQyxKqu1E5nM86CTVg4X21DaiaF0sIQn2RCioFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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