SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca783f03ba563a40193bf2c09721d4ea2ede0dd90c926495577e5399801ec17c' 
  AND token = 'IIaqOUE0sM2eXJcHDtBKZ5T3JXgcKI7Hzla+z0d70e8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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