SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a06ecac492718a45cda10796b6dd86fc3de6064d5e6142174b7b982c14103fc9' 
  AND token = 'knW42LbW2PMRnuK/hT63NH9Udw1to0Jn2i+YuUSaa28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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