SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a2faac1a9c20f58001f4d7b00dcba330f6670f29b3a7bdaa0636cec5eebb96e4' 
  AND token = '7fJzjAf/nGF56CZ1Dj6DpVeG3bhiRB+zM6Qv9NiXnOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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