SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bb6e9b4ca22058c8f9d0aeb0198ded3f14c8c175e8f6b687ee1b01c0495a010' 
  AND token = 's0/YMMkzDQwTICtOOLEYWUhxRImcXuXugCTtxnyVhkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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