SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e986f0d3f8815579d6a75fdd0744b9955cbaea619223c62801f48cee0ed70c4a' 
  AND token = 'QasbZP0OwQPRm6/ttcgngKdOHiRcG8YxMRSEQvz1kKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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