SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eac3f6a746e7cf039fa4104b2e8f2b2e28c0884db31528b682e8ea0652020dc6' 
  AND token = 'yX7BYpdc3f9S9XA0lVKAyOTseteCmR+XWY+vn9lBzhE=' 
  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"
    }
  }
}