SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e72a8af9a1bbcf1f51aa021aeae674b5981b9adb941767a7ff2c6f77865dc6bb' 
  AND token = 'YoFGK0Ml+JLjbmosHphzEchOR8slTDi6PCBfMZBZ8Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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