SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec68bf8d9605999fca28a2ec1d46b540ea7694139f04283d1345b694cf1738b' 
  AND token = 'QReHw2CrPFp7OjNGlUbOt95K21xGUVFPU9XPkL2ZzCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}