SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23e451d58e819f5671220da318285ec60bb61e8314f444d0e7f3ae634b4b121b' 
  AND token = 'QxfhrqLB8lxCwnStViUvzmObuAdoONkOA1t+1fTewpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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