SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3f3c71e7fafe1648aba1aadef12b038b45b993e3d7f5f46316b95b552894d63' 
  AND token = 'i6EosRkF7GVrWWTpftMAyTGk5ny/s5HwU5z5WL4CC/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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