SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf3a1ead38564b4e995882c812cda949d4447062d61499b948325a6c9de40721' 
  AND token = 'YqUiyKOFtEiJjRx/aMhnQ3WiL3zFHCttEAXyvDwc5Uc=' 
  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"
    }
  }
}