SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2b2eaffd16bf65f8090bdc61dedb779388abd02c95b657651d3544cb49251c2' 
  AND token = '0ZkBQfvkqgiXf1yYSNxSiMJ4yxUxGg+aSc6iXduCBR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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