SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d8733a90ec336cc67230d44706db045da323fe9db3e78f81a53352712e5c1ad' 
  AND token = 'kyFbUhQrd/rL3VR0VwV4nAXr8w0lDTWSvrE8JDb3ygM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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