SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b63f274993d09ed8093e834f84990c3c27fea275e9f38dd5d3a66f7c061c9e29' 
  AND token = 'iwvyZmcCMkiyEcrV2GbR741FjqAOBJNaPKXO837gJ6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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