SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f98b3f6e92cd7a88b9222a381309eb4944d3f071685b98743325fbd935fe76c' 
  AND token = 'YPHICGbllO6PJSOs+VdXKwkIGHAUGlPTuIxXnQK0xFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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