SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fea3a529e8450ead899dc942e6a464fbb031027ec8bb4132e88e6ccabd9a2915' 
  AND token = 'uqgQZptrg6ZS6MfmrMGA50Sq4IfnaLgIIWRkadsc0Qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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