SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5d146d8bccd27331dbd4263b884eb83ad897a1052b8f56dac08941ff479d437e' 
  AND token = '66RQsQnmH688KztbfKaqmIo65wGHaxSCPSKHvrXlvJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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