SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9ff86f8f96175f358d34730444c141e2514659e0da745f649723e17c71c2a30' 
  AND token = 'VsQUIZiWBqJfk3ImohWCJJAcEalgS0RdBMcEyeSheXI=' 
  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"
    }
  }
}