SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4f86664aa2efb3f8576d93b0173f921ea2beef9e02b29c7d8b2194683768322' 
  AND token = 'B6lbADtJJi0Skm4TG1L6ChuG/ni2sJv9F6HNs+qTMbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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