SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '594811b68d26dea7e42dc98728a2a50ee47d1413e7c3d606130ceff9c5c8c10d' 
  AND token = 'arht0xDl6P3ceVt19rLcob52yGHiMB1+HVdUbibG1BY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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