SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c9fb5780729ef5a8a099c2d76dd5ce58248e81351b5d99827af7e0c65a26736' 
  AND token = 'NX5ST49bMazxjCHK8GVyxPZSRnXQIBgqfvLhRLfvZVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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