SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b73da9540875ae2b4b690bc136a824f775131ea66fd268dcf262d672f6acd1c2' 
  AND token = 'dTu7MxFvFtRswoHLG2JiPQ8/ZX1OSyZciwaOHkVuS9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}