SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3e51d6123fa4980c3f33ef6f5e225b431323bf1e3109e2b45369c0c8069460b' 
  AND token = '/N6rfhmX/m4MmUVI93VskVEIyaFYJdftS/QFCSij/o4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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