SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78875d93b3582aa6cfa54c841bf347ab450c62b6f290e95c8e761623394bbe9a' 
  AND token = 'W6YxIIGu4kUfAN17o3q6KRd8G4eha75ZsqS2je4TKGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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