SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4794d57b42ec2977bdd3ce48e5c4fcc51bdcbd522f6dc9a3eae3510ed05bc74' 
  AND token = '7Uj1aUiA0MrIl9qARrp8twVKkfF9JC6+4yjm6zoKSPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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