SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e3a0c376f341211ea4acbf928030426b3ad5f19d928d2edd0a4c8a1d395fd14' 
  AND token = '3bFlVBmwbBJyVHGtNPXx2OMpN+z6Yg99qk2P5eiWvgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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