SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c21128c6e3400f62bd85e1e80a02cc2f6baa0517edd0b0fd879f714e1a0be27e' 
  AND token = 'h01p6eirowhlUKFoQqhRLAmrMH1CNZT/oG6RyO1h1BI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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