SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e92838f822e1b281a0851973f92aab8b0789b6f4ebddd36bf9e7cdfdeb90f451' 
  AND token = 'lEOkDE7AasLcKaeOKv8rGFmYI8i7Q9F5szWVejgkTrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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