SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efbeb7939cd10bba6769a9d0da5869064553c589f0ff807af5dd1356f9257f01' 
  AND token = '2xWLUftwwXunMZHedmHcwDibAYVeOo3YStEVLom/FWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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