SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1575ca0ecfcd72ee8bdd72516cdc5408fa7e825848cd2134ebea47cf9556dcd' 
  AND token = 'rLr9NpGFbcpSkGSxewJUjgucDZIW1r4OEoGxw1LKaRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}