SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '862c489f99b1eb81b18752f46062c636a725a0f75db735a13b93c4bacd9e39d2' 
  AND token = 'W61Uf4BVmVXtvpT2e6gl3d39VdmWBTRVkzhFQZIrqnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}