SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71cdb43d31e3050c95a453c4477803681259bf5e73d93f09ce3dcdcbfa644cf1' 
  AND token = 'O+QZWZqT+d0zbnm5Fs5wr1MRMC5RRQzkzHwjiPqOC/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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