SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa19f15a32f577ff4ad1f2acc8c66d4e8736d3526f7b708ca92f9bb7cb70e968' 
  AND token = 'WnK3CEo3vJxOZz+bHRDBVXYpjQz7m5w+x/1wttIEktQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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