SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efeb772d843e3965859660e56d15db7b099d2f86a5f610b98d94443295188134' 
  AND token = 'D93ky8pDSOcCCV1uHMIREwCY18YLBIpe+qyMCIkT6yY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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