SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c89686516893d79f307042667e5db075c7c49d3a86370e999f9f6dd8802da5e' 
  AND token = 'Op83lhTvncO+/K/KbJMCP0ZvN683HIWQycNBvBGRQBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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