SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d2cdb49aefcfc0c8b573c46c4945e7f4a485ff7561bb3d1d46945ba8eb75629' 
  AND token = '7nagag/aeOik860kKFLXkTsN1wI2fi1ssxlQ3AMGn5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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