SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12afe6185b2b0dc2a5a8956524ad0a8a67d72e3b3714098c76e659a6f5b75519' 
  AND token = '5vLAaqmQshW3tki5hgBPzGLeEpHonaInZNv6PpKfq+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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