SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '307cdce88cbd9d32b2e631d10d847081ad67e8d35efabd69a15a7f19654823e1' 
  AND token = 'NQqqVFC+EoLac72+iCF5dLXIMnSDBQlkJWWV4voPcb4=' 
  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"
    }
  }
}