SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3b3e4db426917b151d8f2e25bdf6491175dc58251d6ec24c072a3f408c67659' 
  AND token = '1fX0osn6AiRdEzSndTEc/lUMNs+C4zlwJC+BqU9iHKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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