SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9e9ac87147ef638617cf719fdf53f7f05f8dfe0013a6c6478fe3f957be6ace8' 
  AND token = 'wgNe9CLGa5AvqDsfV+oigKbNMO8n/CpEJFmk2+xWJKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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