SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6102ad4ec271009f9eb16fa09d04a3f1b5d373605d128d8fa87a6c350c2b59e' 
  AND token = 'g01vllZs76rV35FhYbZQYUis3DfAv/o/aui0i6XOIF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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