SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c13f7b02891c17f627a53d8716019ee98db0c91c374392746a739b68ee69c656' 
  AND token = '6i1yQuyzXIx9AV5ope+r3BOTfiYaFbCT5I+idNcBtNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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