SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '298fae23e08d30e992be185ba1ba2ccc2b2bcfa614e6a6d7512ad91f4e847462' 
  AND token = 't/zigYQ/lZBpYT3I+PVXSKU+nBwaFUc86pSxBBPF07w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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