SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da85ea9f9247a071a2ef956c1946078d1249c935bbb0379a0e58020f50e9a217' 
  AND token = 'YlzStjE5ivTFcf28ugR9OIkExxiGSd3ZProH2GjOsgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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