SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a47a042e12ef2e9b3e350eb55c6a50ec5db4a78ae012b4fe28884967bd07f35a' 
  AND token = 'uDrqQ2UHXiy2x7/mR/EdH0iuYOiM4BPFWwMKOUtwj5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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